Istanbul - When General David Petraeus took over as commander of US forces in Iraq 19 months ago, the country was on the brink of civil war.
More than 3,000 US soldiers had died since the invasion of March 2003 and al-Qaeda terrorists had made the western province of Anbar their regional centre of operations.
With a new strategy that included a surge of US troops, Iraqi military helpers and improved surveillance, Petraeus was able to change the picture.
But for his successor, General Raymond Odierno, who on Tuesday took charge of the 146,000 US troops in Iraq, a lot of problems remain.